Friedrich zu Solms-Baruth was swept up by the Gestapo the day after a failed 1944 bombing attempt on Hitler and thrown into the secret police's notorious Prinz Albrecht Strasse prison in downtown Berlin.

Unlike scores of others connected with the Kreisau Circle of plotters who were executed, the German aristocrat was eventually released — but not before he had signed away ownership of his family's estates on the order of Gestapo and SS chief Heinrich Himmler.

Now, some 60 years later, Solms-Baruth's grandson is continuing the family's fight for compensation for the millions of dollars (euros) in lost property, taking his case to court.

"My father did it for his father, and unfortunately didn't live to the day to see justice served ... therefore I am virtually making this a life's quest," Friedrich zu Solms-Baruth, who shares his grandfather's name, told The Associated Press in a telephone interview from Barcelona, Spain, ahead of a Thursday hearing.

"It's really absurd that we should be talking about something like this today, when it's obvious a man who was imprisoned after the assassination attempt, with virtually a noose around his neck, was forced to sign his properties away."

The question the court will decide is when Solms-Baruth's grandfather lost his properties: when he signed away power-of-attorney in the Gestapo prison, but remained the official owner on the books, or when the area was occupied by the Soviet Union immediately after the war and all large estates were seized and land redistributed.

If the latter, German court decisions since reunification have ruled former land owners have no claims.